feat: Add unit tests and fakes for Crestron environment and data store

- Introduced `FakeCrestronEnvironment` and `FakeEthernetHelper` for testing purposes.
- Implemented `InMemoryCrestronDataStore` to facilitate unit tests for data storage.
- Created `DebugServiceTests` to validate the behavior of debug-related services.
- Added project files for unit tests targeting .NET 9.0 with necessary dependencies.
- Developed production adapters (`CrestronConsoleAdapter`, `CrestronDataStoreAdapter`, `CrestronEnvironmentAdapter`, `CrestronEthernetAdapter`) to interface with the Crestron SDK.
- Updated `Debug` class to utilize injected service abstractions instead of direct SDK calls.
- Enhanced `ControlSystem` initialization to register service adapters before usage.

src/PepperDash.Core/Adapters/CrestronEthernetAdapter.cs

@@ -0,0 +1,39 @@
+using System;
+using Crestron.SimplSharp;
+using PepperDash.Core.Abstractions;
+
+namespace PepperDash.Core.Adapters;
+
+/// <summary>
+/// Production adapter — delegates IEthernetHelper calls to the real Crestron SDK.
+/// </summary>
+public sealed class CrestronEthernetAdapter : IEthernetHelper
+{
+    public string GetEthernetParameter(EthernetParameterType parameter, short ethernetAdapterId)
+    {
+        var crestronParam = parameter switch
+        {
+            EthernetParameterType.GetCurrentIpAddress =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_CURRENT_IP_ADDRESS,
+            EthernetParameterType.GetHostname =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_HOSTNAME,
+            EthernetParameterType.GetDomainName =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_DOMAIN_NAME,
+            EthernetParameterType.GetLinkStatus =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_LINK_STATUS,
+            EthernetParameterType.GetCurrentDhcpState =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_CURRENT_DHCP_STATE,
+            EthernetParameterType.GetCurrentIpMask =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_CURRENT_IP_MASK,
+            EthernetParameterType.GetCurrentRouter =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_CURRENT_ROUTER,
+            EthernetParameterType.GetMacAddress =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_MAC_ADDRESS,
+            EthernetParameterType.GetDnsServer =>
+                CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_DNS_SERVER,
+            _ => throw new ArgumentOutOfRangeException(nameof(parameter), parameter, null),
+        };
+
+        return CrestronEthernetHelper.GetEthernetParameter(crestronParam, ethernetAdapterId);
+    }
+}